Micro‐Doppler detection in forward scattering radar: theoretical analysis and experiment

Abstract

Forward scatter radar (FSR) is actively studied in the field of radars, as it has many advantages such as robust to radar absorbing material and possibility in target recognition. In many radar systems, micro-Doppler signature is one of the most distinguished information used for target recognition. Yet, there is lacking in established work on investigating the feasibility of using FSR to detect and analyse micro-Doppler signature generated from micro-motions of moving targets. Hence, a theoretical and experimental investigation of using the FSR to detect micro-Doppler signatures is presented. The preliminary results for both theoretical and experiment investigations verified that the FSR system is capable to detect the micro-Doppler signature for a swinging pendulum attached to the moving trolley.

Extraction of Doppler signature of micro‐to‐macro rotations/motions using continuous wave radar‐assisted measurement system

“…Typically, N is 2 for drone/UAV/quadcopter propeller and it varies from 2 to 6 for helicopters of different radar cross-section (RCS) and payload capacity [13,14,25]. More than one rotating target or a target having multiple rotating parts can be distinguished based on the micro-Doppler frequency and range profiles generated by them [13,26,27]. Whole body and parts of a walking/jogging/cycling person can be distinguished by carefully analysing the micro-Doppler spectral signatures [21,28].…”

Micro-Doppler Estimation and Analysis of Slow Moving Objects in Forward Scattering Radar System

“…When the pendulum exactly crosses the baseline, the frequency and amplitude of Doppler signature are equal to zero. At the baseline the Doppler frequency equals zero because the bistatic angle β pen equals 180 • as depicted in Equation 4, and the amplitude becomes minimum or zero because the direct and scattered signals are equal and opposite each other in phase [18]. The BL crossing points are marked by circles.…”

“…where is the tangential velocity of the pendulum, which is previously given in (18), and is the translational motion due to the linear motion of the pendulum's assembly point (pivot In this case, the pivot of pendulum p moves linearly from y max to −y max along the Y-axis while the pendulum mass is swinging. Therefore, the coordinates of pendulum mass changes with time due to: (i) the vibration motion of pendulum; and (ii) the straight motion because of linear translation motion of its pivot point p. In Figure 4, the instantaneous translational coordinates of the pendulum mass are as follows:…”

“…where V Pen−Tang is the tangential velocity of the pendulum, which is previously given in (18), and V trans is the translational motion due to the linear motion of the pendulum's assembly point (pivot point).…”

“…Despite the advantages of using the micro-Doppler in target classifications, no results have been published for studying the capability of using the FSR to detect the micro-Doppler, except our research group published paper [18]. Nevertheless, there is still a need for more studies, investigations and improvements on using the FSR for micro-motions detections.…”